Generally, hybrid vehicles have a clutch, a motor, and a transmission disposed on a power delivery path formed from an internal combustion engine to a wheel; and a hybrid starter and generator (HSG) disposed on the engine to start the engine or to control a rotational speed of the engine.
The clutch performs an engine brake function, such that torque is transmitted from the wheel to the engine through the transmission, the motor, and the clutch, wherein a part of the torque generates electricity through the motor. An accurate braking force cannot be realized because the torque is transmitted through the transmission.
Further, because the motor performs charging and discharging, a regenerative braking torque changes depending on a state of charge (SOC) of a battery, which operates the motor and the HSG, thereby making it harder to realize a secure braking force.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.